Needle-thread-controlling device for sewing-machines.



J. S. FINCH.

NEEDLE THREAD CONTROLLING DEVICE FOR SEWING MACHINES.

APPLICATION FILED OCT-8,1915.

Patented July 24, 1917.

WITNESSES. l/VVEIVTDI? X0 Jaw/v 5 FFA/UH ATTORNEY v 1 NlTED STATE PATENT JOHN S. FINOI-I, 0F BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE SINGER MANUFAC- TUBING COMPANY, A CORPORATION OF NEW JERSEY.

NEEDLE-THREAD-CONTROLLING DEVICE FOR SEWING-MACHINES.

Application filed October 8, 1915.

To all whom it may concern:

Be it known that 1, JOHN S. FrNon, a citizen of the United States, residing at Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Needle- Thread- Controlling Devices for Sewing- Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to improvements in needle thread controlling devices for sewing machines and has for its object to control the action of the thread-check mechanism through the manual manipulation of the thread tension device.

In the stitching of, so termed, wide throw zigzag seams it is essential to the convenient manipulation of the fabric that the needle thread pass freely from the supplyto the needle eye whenever it is desired to remove the fabric from beneath the presser-foot or readjust the same with respect to the latter, and to this end the tension device and thread-check are operatively connected with the presser-foot lifting mechanism to permit of the convenient withdrawal of the thread at such time as the presserfoot occupies its elevated position.

Referring to the drawings, which form a part of the specification, Figure 1 is a front side elevation of the present invention, together with so much of one variety of zigzag sewing machine as is essential to an understanding of its construction and application. Fig. 2 is a view in front end elevation of Fig. 1. Fig. 3 is a plan view, partly in full lines and partly in section, illustrating the means employed for operatively connecting the thread-check and tension device with the presser-foot lifting mechanism, and Fig. f is a view, partly in full lines and partly in section, of the thread-check and means for operatively connecting it with the main or needle-bar actuating shaft.

The present invention is shown as applied to one variety of Singer zigzag sewing machine, but as it relates only to the construction and application of improved means for controlling the withdrawal of the needle-thread. from the supply, only such reference will be made to the other elements.

of the machine as is essential for a proper Specification of Letters Patent.

Patented July 2%, 1917..

Serial No. 54,720.

understanding of the invention, and as the common parts are very similar in all machines of the present class the invention can be applied to any of them with little or no change.

1 and 2 represent the front end portion of the sewing machine bed-plate and bracket-arm respectively, the latter being provided with the usual head 3. 4 and 5 represent the loop-taker driving shaft and the main and needle-bar actuating shaft respectively, the latter carrying the shaft flange 6 from which motion is transmitted to the take-up 7 and stitch-forming movements to the needle carrying bar 8 provided with the needle 9, the loop-taker driving shaft being operatively connected with the loop-taker 10' through the gears 11 and 12.

13 represents a spring depressed clothpresser carrying bar provided with the cloth-presser frame 14 carrying the clothpressers, as 15, the cloth-presser carrying bar being provided with a slidably mounted cloth-presser lifting tube 16 having formed integral with it a bracket-arm 17 yieldingly held by spring 18 in effective relationship with the cam portion 19 of the cloth-presser lifting lever 20, the spring 18 being seated at one end in a suitable opening (not shown) formed in the lug 21 carried by said lifting tube, the opposite end of said spring abutting the lower wall of a collar 22 carried by the cloth-presser carrying bar, said collar being provided with a guide-arm 23 which tracks a slot 24 formed in a depending guide bar 25 suitably secured in the head of the bracket-arm. Such elementsof the cloth feeding mechanism as are included in the present figures are designated by the numeral 26.

27 represents a swinging frame pivoted at its upper end on a stud 28 secured in the head of the arm-bracket and into which is mounted to move vertically the needle-bar 8, the lower end of said frame beingpivotally connected, by stud screw 29, with one end of a connection 30 whose opposite end is operatively connected with common means (not shown) for transmitting to said frame and needle-bar lateral movements in a direction transverse to the feed movements of the fabric. All of the foregoing elements are common to machines of the present class and are herein shown as best representing one form of construction to which the present invention is applied.

31 represents a bushing threaded into the arm-bracket and bored to receive the threadcheck releasing plunger 32, collar 33 carried by said plunger and spring 34, the latter acting to resiliently hold the thread-checks, as 35, in thread gripping relationship, the opposite end of said plunger 32 cooperating with the periphery of the ring 36 to release such gripping action at substantially the time the take-up is actuated to set the stitch, said ring being mounted to turn on the eccentric 37 carried by the main-shaft 5. 38 denotes a plunger cap secured by screw 39 to the outer end of the plunger 32, said cap being cupped to receive the spring 40 and provided with a peripheral groove 41. The spring 40 exerts a slight pressure on the disks 35, sufficient to hold them against accidental movement in a direction away from the outer end of the bushing 31 and effect a slight tension on the thread.

The needle thread tension device is of common construction and comprises the thread tension stud 42 secured in the head of the bracket arm, and upon said stud is loosely mounted the tension disks 43 and 44, and in front of said tensiondisks is.

mounted a tension releasing disk 45 provided with ears 46, 47 and 48, and between the latter disk and the tension nut 49, threaded onto the free end of the stud 42, is arranged a volute spring 50 which acts upon the thread tension disks to tension the needle-thread and through the adjustment of the nut 49 vary the degree of tension to meet the requirements of the product, the

tension device being provided with the usual thread controller spring 51 and thread controller stop 52.

53 represents a tension releasing disk pin extending inward from the disk 45 and into an opening 54 formed in the head of the arm-bracket, said pin abutting one end of a thread-tension releasing plunger 55 having an enlarged portion 56 and rounded free end 57, which latter cooperates with an incline 58 of an arm 59 carried by the cloth-presser lifting tube 16, the free end of said arm having an upwardly extending lug 59' provided with a vertical wall 59", which latter engages the plunger 55 except when the tubular portion 16 is moved upward by the presser lifting lever 20 suflicient to bring the upper end of said tube in engagement with the collar carried by the bar 13, When the inclined portion 58 is caused to engage said plunger. The purpose of the spring controlled lost motion existing between the tube 16 and cloth presser bar 13. is to permit of an upward movement of the cloth-presser carrying bar sufficient to meet the requirements of seams and other increased thickness of fabric passing beneath the cloth-presser without disturbing the normal action of the thread tensioning devices, the arm 59 being held against accidental movement about the axis of said tube by a stud screw 60.

61 denotes a thread-check releasing lever pivotally connected at 62 to a stud 63 secured in the arm-bracket 2 by screw 64 and provided with a pin which enters a groove 40 in the cap 38 for a purpose later to be explained, the free end 66 of said lever being in engagement with the outer surface of the car 46 of the tension releasing disk 45, thus effecting achain of connections between the presser lifting-lever 20 and the needle thread tension device and between the latter and the thread-check mechanism.

Having set forth the details of the invention, the following mode of operation and cotiperation of the several parts will be readily understood.

In the operation of the machine the cocentric 37 carried by the main shaft 5 acts, through the ring 36, to move the plunger 32 outward once for each complete actuation of the stitch-forming mechanism a distance suflicient to releasethe action of the spring 34 on the disks 35, thus allowing the thread to pass between said disks under the action of the spring 40 at substantially such time as the take-up is actuated to set the stitch, and when, for any purpose, the clothpresser carrying bar 13 is elevated by the manipulation of the cloth-presser lifting lever 20 the incline 58 of the arm 59 carried by the cloth-presser lifting tube 16 effects a forward movement of the thread tension releasing plunger 55 which, through the pin 53 and disk 45, acts to open the tension disks 43 and 44, the disk 45 acting also to move the lever 61 outward which causes the plunger 32 to be moved in opposition to the resilience of the spring 34, thereby freeing the disks 35 from the pressure exerted by the latter, thus releasing the needlethread from control by the thread tension device and thread-check spring, 34.

Having thus set forth the nature ofthe invention, what I claim herein is 1. In a needle-thread controlling mechanism for lock-stitch sewing machines, the combination with a cloth-presser and a cloth-presser lifting mechanism including a cloth-presser carrying bar, a needle-thread tension mechanism carried by the sewing machine bracket-arm and connections between said tension mechanism and the clothpresser carrying bar to release the tension on the needle-thread when the said bar is actuated to move said cloth-presser out of engagement with the fabricbeing acted on,

connected with said tension releasing device and by the latter controlled to lessen its of a thread-check mechanism operatively gripping action on the needle-thread simultaneous With the release of said thread by the thread-tension device.

2. In a needle-thread controlling mechanism for lock-stitch sewing machines, the combination with a clothresser and a cloth-presser lifting mechanism including a clothresser carrying bar, a needle-thread tension mechanism carried by the sewing machine bracket-arm and connections between said tension mechanism and the clothn-esser carrying-bar to release the tension on the needle-thread When the said bar is actuated to move said clothresser out of engagement With the fabric being acted on, of a thread-check mechanism-and connections, including a lever pivoted to a stationary part of the sewing machine, for operatively connecting said tension device With said thread-check mechanism, said lever acting to lessen the gripping action of said thread-check on the needle-thread simultaneous with the release of said thread by the thread-tension device.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing Witnesses.

JOHN S. FINCH.

Witnesses:

STANLEY N. SMITH, H. M. BURR.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. O. 

